In a multiple-input multiple-output (MIMO) radar, it is desired to maximize the power radiation in an angular region of interest, which, however, is hardly achievable because a set of orthogonal waveforms is employed at the engineering. Different from traditional colocated MIMO radar, space-time coding array (STCA) transmits an identical waveform with a tiny time delay circulating across array elements. It can provide a simple way to achieve the full angular coverage with a stable gain. In this paper, a new scheme referred to as chirp-STCA is proposed to synthesize the desired beampattern flexibly. With the quantitative relationship between the time delay and the span of beam spreading, the transmit beampattern synthesis issue is converted to the design of time delay value which can be readily realized based on the framework of chirp-STCA. As a result, the desired angular sector coverage of the radiation power can be realized by setting a proper time delay. The proposed chirp-STCA can provide many desired features including low range sidelobe level, low computational complexity, and constant modulus. In addition, the range-angle properties are examined by analyzing the transmit beampattern response and the ambiguity function. Numerical results are presented to demonstrate the effectiveness and simplicity of the chirp-STCA scheme for the transmit beampattern synthesis.

在多输入多输出（MIMO）雷达中，期望最大化感兴趣的角度区域中的功率辐射，但是，由于在工程上采用了一组正交波形，因此这是很难实现的。与传统的共置MIMO雷达不同，空时编码阵列（STCA）传输相同的波形，但在整个阵列元件之间存在微小的时间延迟。它可以提供一种简单的方法来以稳定的增益实现​​整个角度范围。在本文中，提出了一种称为chirp-STCA的新方案，可以灵活地合成所需的波束图案。利用时间延迟与波束扩展范围之间的定量关系，将发射波束模式合成问题转换为时间延迟值的设计，可以在线性调频STCA框架的基础上轻松实现。结果，可以通过设置适当的时间延迟来实现期望的辐射功率的角扇区覆盖。提出的线性调频STCA可以提供许多所需的功能，包括低范围旁瓣电平，低计算复杂度和恒定模数。另外，通过分析发射波束模式响应和模糊函数来检查距离角度特性。数值结果表明了线性调频STCA方案在发射波束图合成中的有效性和简便性。通过分析发射波束模式响应和模糊函数来检查距离角度特性。数值结果表明了线性调频STCA方案在发射波束图合成中的有效性和简便性。通过分析发射波束模式响应和模糊函数来检查距离角度特性。数值结果表明了线性调频STCA方案在发射波束图合成中的有效性和简便性。